yeap bro, cos its the same chip on the same PCB - the only thing differenet about the 6770 is that it has a 100~200MHz heightened clock speed. Its the same story as the G92(i think) chips from Nvidia - in reality die shrunk 8series cards
I'd also advise the OP to stay away from the 5830 - it might seem like a good buy at first with its prices, but you didn't read the fine print ; the 5830 has the same PCB and power delivery as the other 58xx cards and thus has the same power draw as a 5850 so price/performance/power ratio is a total fail. AMD wanted to reuse the chips that were being binned and they came up with the 5830. BTW, the same goes for a 6790 - total fail in that department.
All in all get the 5770 and you can manually OC the speeds in the performance tab in catalyst.
*6000 series cards should've been good as they were about 3D on an eyefinity setup. The 6770=5770=only eyefinity
a higher clock speed from both 6770 cards could give a slight lead against 2x5770 - maybe
they use the same drivers.......
with the release of each driver, they are actually decreasing the number of elements to tessellate/process, thus the cards SEEM
to run smoother e.g: with Crysis 2 is that initially with my 6870 BE on catalyst 11.3~4, i had to do an overclock to QX9770 specs and get a good experience. Now with 11.5, i don't need the OC. The drivers are being written in such a way that old and new AMD cards can process the same game Nvidia cards previously dominated(due to physx and its architecture) thus the drivers are toning "down" the game features to help AMD cards process better. Same goes for H.A.W.X 2